International Journal of Chemical Studies 2018; 6(2): 2713-2718 P-ISSN: 2349–8528 E-ISSN: 2321–4902 IJCS 2018; 6(2): 2713-2718 Status of coconut black headed caterpillar, © 2018 IJCS Received: 13-01-2018 Opisina arenosella (Walker) and it’s associated Accepted: 19-02-2018 larval parasitoid, Goniozus nephantidis SS Gurav (Muesebeck) under south Gujarat conditions Ph. D Student, Department of Entomology, N. M. College of Agriculture, Navsari Navsari Agricultural University, SS Gurav, GG Radadia, CU Shinde Navsari, Gujarat, India Abstract GG Radadia Roving survey has been carried out in major coconut growing talukas of Navsari district viz; Navsari, Professor and Head, Dept. of Jalalpore, Gandevi, Chikhali and Vansda to know the exact status of the pest black headed caterpillar and Entomology. Department of Entomology, N. M. College of its associated larval parasitoid, G. nephantidis during the year 2015-16 and 2016-17. Pest incidence, Pest Agriculture, Navsari intensity and Parasitization percentage has been recorded during survey work. Overall survey results Navsari Agricultural University, revealed that pest incidence of coconut black headed caterpillar, O. arenosella was observed in all Navsari, Gujarat, India talukas throughout the year in the range of 18.79 to 54.92 per cent in Navsari district. Maximum pest incidence was recorded in Vansda taluka (54.92%) and minimum pest incidence was recorded in Navsari CU Shinde taluka (18.79%). Pest intensity was in the range of 8.61 to 52.95 per cent in various talukas of Navsari Assistant Professor. Department district. Maximum pest intensity was recorded in Vansda taluka (52.95%) in the month of April while of Entomology, N. M. College of minimum pest intensity was recorded in Navsari taluka (8.61 %) in the month of January. Pest incidence Agriculture, Navsari and pest intensity trend showed that peak incidence was recorded during summer months that are from Navsari Agricultural University, April to May while it decreases from September onwards and reaches to minimum in winter months Navsari, Gujarat, India November and December. In case of percent parasitization, G. nephantidis was the dominant parasitoid under Navsari conditions of Gujarat state. Maximum parasitization was observed in Navsari taluka in the month of May (11.76 %) followed by April (10.07 %) while lowest was 2.63 per cent in Chikhali taluka in the month of May. Keywords: Coconut, opisina arenosella survey, goniozus nephantidis 1. Introduction The coconut palm, Cocos nucifera L. belongs to family Arecaceae is one of the traditional crops known as “Kalpavriksha” as well as “Tree of Life” provides food, shelter, fuel, medicine and employment to billions of people across the world. Coconut is widely cultivated in all the tropical regions of the world. India is third leading country after Philippines, Indonesia in harvested area of coconuts among the Asian countries. In India, coconut is grown in Kerala, Karnataka, Tamil Nadu, Andhra Pradesh, Orissa, Maharashtra, West Bengal and Gujarat. [17] (Venkatesan et al. 2008) . Now a day, coconut plantation is continuously increasing in Gujarat state especially in south Gujarat and coastal areas of Saurashtra. The coconut palm is infested by a number of insect pests. Among them coconut black headed caterpillar, O. arenosella (Lepidoptera: Crytophasidae) stands out as predominant leaf feeder. This is one of the serious and endemic pests of coconut in India (Cock and Perera, 1987 and Rukhsana and [12] Majeed, 2014) . The caterpillar is gregarious in habit and is voracious feeders. It feed on the parenchymatous tissues on the under surface of the leaflets and construct galleries along with silk and excreta. Under favourable conditions, the pest multiplies rapidly and devastates the leaf lamina. This caterpillar attack palms of any age from nursery to grown up plants causing the severe damages to the foliage, depriving the palm of its photosynthetic area and thus, [14] directly affecting the yield reduced to half (Subaharan,2008) . Outbreaks of the pest occur Correspondence usually under favourable congenial conditions. Moreover, the infestation of pest under south SS Gurav Gujarat conditions reaches serious proportion during the hot months of March to May; Ph. D Student, Department of thereafter sharp that declines of population the pest due to the onset of monsoon. The Entomology, N. M. College of abundance of the pest directly correlated with the relative humidity and inversely proportional Agriculture, Navsari Navsari Agricultural University, to the temperature and sunshine hours (Kapadia and Mittal, 1993 and Pushpalatha and [7, 10] Navsari, Gujarat, India Veeresh, 1995) . ~ 2713 ~ International Journal of Chemical Studies Among various control strategies, biological control is living weapon and excellent strategy over chemical control. Among all parasitoids, G. nephantidis is one of the gregarious larval parasitoid responsible for the reduction in pest population under field conditions to the extent of 60 to 70 per cent. Hence, G. nephantidis is being widely used in the biological control programme (Venkatesan et al., 2007) [16]. In Gujarat, coconut climbing is very expensive due to non availability of expert climbers and the farmers are very reluctant to adopt the pest management practices in the crown area due to this difficulty. The potent bio agent, G. nephantidis may be recommended as larval parasitoid for management of black headed caterpillar. Keeping these in view, the present survey Fig 3: Heavy infestation of coconut black headed caterpillar work has been undertaken to know the exact status of the pest as well as parasitoids under South Gujarat condition. 2. Materials and Methods The roving survey of O. arenosella and associated larval parasitoids was carried to know the incidence, intensity and natural parasitization of larval parasitoids on coconut plantation at an interval of one month in Navsari, Jalalpur, Gandevi, Chikhali and Vansda talukas of Navsari district during the year 2015-16 and 2016-17. Observations were recorded as per methodology suggested by All India Coordinated Research Project on Palms, Central Plantation Crop Research Institute, Kasargod, Kerala (Anonymous, Eggs Larva 2015) [1] (Fig 1 to 5) Pupa Adult Fig 4: Life stages of O. arenosella Fig. 1: Survey area in Navsari District Fig 5: Leaf scrapping by larva 1) Pest Incidence: To know the per cent pest incidence of O. arenosella, two coconut fields were selected from each talukas. In each field, number of palms infested with O. Fig 2: Recording observations during survey work in Navsari arenosella will be recorded from total palms. Per cent pest District incidence was calculated by using following formula, ~ 2714 ~ International Journal of Chemical Studies Total number of palms healthy and infested leaves were counted. Among total damaged Pest Incidence (%) = X 100 infested leaves, 20 per cent leaves were selected for critical Total number of palms observations. Thereafter, each selected leaf was divided into observed five parts as per given scale. Out of five parts, middle part of leaf was selected for the presence of egg, larva, pupal cases 2) Pest Intensity: The pest intensity was calculated by [13] and adult stage. Numbers of insects were counted. These employing methodology suggested by Sathiamma (1993) . numbers were used for estimation of the pest intensity To know the pest intensity, two coconut fields were selected (percentage) by using sampling formula regression equations from each taluka. In each coconut field, 10 infested palms as given below. were selected. From each selected palm, total numbers of Period Regression Equation February to March Y = 22.59 + 5.75 X April to June Y = 38.40 + 9.70 X July to October Y = 20.57 + 6.20 X November to January Y = 6.36 + 8.99 X Where X = Total no. of observed stages Y = Pest Intensity (Eggs, Larva, Pupa and Adults) 3) Percent Parasitization: In order to know the natural parasitization of G. nephantidis; ten randomly infested leaflets Total number larvae were critically examined and larvae of O. arenosella were Percent parasitized by parasitoids = X 100 collected and brought to Bio-control Laboratory, N.A.U. Parasitization Total number of larvae Navsari. These collected larvae were kept in plastic jar for the observed emergence of parasitoid under constant supervision. The count of parasitized larvae was taken out and percent 3. Results and Discussion parasitization of G. nephantidis was worked out by using The results obtain during the present studies are presented in following formula, Table 1 to 3 and discussed hereunder. Table-1: Pest incidence of black headed caterpillar, O. arenosella in different talukas of Navsari district (Year 2016, 2017 and average) Navsari Jalalpore Gandevi Chikhali Vansda Months 2016 2017 Average 2016 2017 Average 2016 2017 Average 2016 2017 Average 2016 2017 Average January 43.86 44.62 44.24 42.59 40.00 41.30 46.30 40.00 43.15 42.00 38.00 40.00 51.52 58.33 54.92 February 45.45 48.89 47.17 44.00 44.68 44.34 50.00 42.55 46.28 44.44 40.74 42.59 45.45 58.18 51.82 March 46.94 51.11 49.02 49.09 45.65 47.37 52.73 45.65 49.19 45.00 41.67 43.33 48.89 58.46 53.68 April 49.25 52.31 50.78 50.00 45.16 47.58 53.23 48.39 50.81 40.68 43.55 42.11 43.64 58.06 50.85 May 52.63 53.97 53.30 51.85 46.67 49.26 48.15 50.00 49.07 40.35 36.92 38.64 41.43 61.11 51.27 June 42.22 39.58 40.90 45.83 43.18 44.51 41.67 47.73 44.70 36.17 34.69 35.43 34.29 42.11 38.20 July 32.76 38.18 35.47 - - - - - - - - - - - - August 32.08 30.91 31.49 - - - - - - - - - - - - September 18.46 19.12 18.79 - - - - - - - - - - - - October 24.53 23.08 23.80 18.37 21.28 19.82 22.45 25.53 23.99 31.91 34.04 32.98 44.62 42.22 43.42 November 26.19 27.78 26.98 24.49 24.44 24.47 24.49 21.74 23.11 32.69 32.00 32.35 49.09 32.50 40.80 December 41.54 25.42 33.48 27.78 23.91 25.85 25.00 23.40 24.20 34.43 31.48 32.95 55.77 29.55 42.66 Note: “ - ” indicated not surveyed due to unavailability of climber in rainy season.